Answers:
No, I do not have a tow mode. I do have an overdrive on/off switch on the shifter.
No, I do not ride the brakes. I brake firmly and release and coast.
Yes, this section works out to 4.356% grade. But it's still 10 miles of a 4.356% grade.
Once again, I was not asking how to drive in the mountains. I was not aware of the grade or the distance until after I was already on it. And there are only a few places to pull off in those 10 miles.
The question I asked was: Which route would you take to get to Yosemite Valley from I-5 Southbound?
The one that is shorter, but climbs to over 6300 ft. (Hwy 120).
Or the longer route that never goes over 4000 ft. and only takes about 25 - 30 minutes longer. (Hwy 140).